\\[-1.8ex] Soil Heterogeneity & $-$0.058$^{**}$ & $-$0.046$^{**}$ & $-$0.049$^{**}$ & $-$0.044$^{*}$ & $-$0.057$^{**}$ & $-$0.037 \\ 
  & (0.023) & (0.023) & (0.024) & (0.024) & (0.023) & (0.024) \\ 
\\[-1.8ex] 
Observations & 14,697 & 14,697 & 14,697 & 14,697 & 14,697 & 14,697 \\ 
R$^{2}$ & 0.823 & 0.832 & 0.828 & 0.828 & 0.823 & 0.836 \\ 
